Methods for producing 2D materials by moving forming layers disposed on carriers through a reaction chamber open to the atmosphere

ABSTRACT

A method of making 2D material such as graphene includes introducing a purge gas into a gas confining space within a reaction chamber to purge the gas confining space of oxygen; introducing a donor gas into the gas confining space within the reaction chamber; moving a forming layer within the gas confining space within the reaction chamber when the donor gas is within the gas confining space; and heating the forming layer within the gas confining space to a temperature sufficient to form 2D material while the gas confining space is open to a surrounding atmosphere.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority as a divisional application ofU.S. application Ser. No. 15/362,146 filed Nov. 28, 2016, entitledApparatus for Producing Graphene and Other 2D Materials, which claimedpriority as a non-provisional application to U.S. ProvisionalApplication Ser. No. 62/262,145 filed Dec. 2, 2015, and entitled LargeScale Machine for Manufacture of Graphene and 2D Materials, the contentsof which are both incorporated by reference as if fully set forthherein.

FIELD OF INVENTION

The present invention relates to the field of a method and apparatus forlarge-scale manufacturing of 2D materials, such as graphene, andparticularly relates to a method and apparatus in which a 2D material isformed on a train of forming sheets moving through a quartz furnace.

BACKGROUND AND SUMMARY OF INVENTION

Graphene and other 2D materials are formed with large two dimensionalcrystalline structures, and they are generally highly useful materials,but they are difficult and expensive to manufacture. A machine andmethod for making such materials is disclosed herein that significantlyreduces the cost of 2D materials, and the technique is scalable, meaningit can be made larger and faster with relative ease.

In one embodiment, an apparatus for producing a 2D material, such asgraphene, includes a forming sheet suitable for growing (forming) the 2Dmaterial, and the forming sheet is disposed on the surface of a carriersubstrate. A furnace is provided in a configuration to form a confiningspace around the carrier substrate and the forming sheet, and theconfining space is open to atmosphere around the furnace such that gasmay flow out of the confining space to atmosphere. The furnace alsoincludes a support configured to support the carrier substrate in thefurnace, and within the furnace, a first furnace surface is disposedimmediately adjacent to and spaced apart from the forming sheet when thecarrier substrate is disposed on the support. In this configuration, avolume is formed between the first furnace surface and the formingsheet, and such volume facilitates gas flow within the furnace toeffectively and efficiently deposit large crystalline structures of 2Dmaterial onto the forming sheet. At least one supply port provides aflow of gas into the volume, and a gas supply provides a flow of purgegas through the supply port to purge the volume and also supplies a flowof donor gas through the supply port and into the volume. A heaterwithin the furnace heats the forming sheet to a temperature sufficientto form 2D material, such as graphene, on the forming sheet when a donorgas is supplied into the volume.

The purge gas is chosen to remove elements, molecules or compounds thatwould interfere with the production of the 2D material. For example,oxygen would typically interfere with the production of 2D material,such as graphene, and oxygen may be purged with a gas such as argon ornitrogen. The donor gas is chosen to supply the material needed to formthe 2D material. For example, to form graphene the donor gas shouldsupply carbon atoms and one appropriate donor gas would be methane. Tomake another 2D material with this apparatus and method the donor gas ischanged to donate the desired element or molecule and the operatingparameters (temperature and forming sheet material) are adjusted for thedesired 2D material.

In the production of 2D material, the furnace may be constructed inwhole or part of quartz. The quartz plate may be used to form the firstfurnace surface, and multiple ports are formed in the quartz plateextending through the first furnace surface for delivering gases to theconfining space in the furnace between the first furnace surface and theforming sheet. Multiple ports are connected to a plurality ofpassageways formed in the quartz plate, and the passageways areconnected to a gas supply. Purge gases and donor gases are transmittedthrough the passageways to the plurality of ports for first purging thevolume inside the furnace and then providing the donor gas to form 2Dmaterial on the forming sheet within the furnace. The heater may bedisposed adjacent to the quartz plate on the opposite side of the quartzplate from the first furnace surface such that the heater and theforming sheet are positioned on opposite sides of the quartz plate andheat from the heater is transmitted through the quartz plate to theforming sheet.

The first furnace surface and the forming sheet are configured so thatthe volume between them has a rectangular cross-section, with the widthof the cross-section being larger than the height of the cross-section.The width is at least 3 times the height but the width is less than1,000,000 times the height. Preferably, the width is less than 1000times the height. The configuration of the volume combined with theconfiguration of the ports and the flow rates of the gases is designedto produce a substantially nonturbulent, laminar flow of the donor gasesacross the forming sheet. The purge gases will also have thenonturbulent laminar flow across the forming sheet which will increasethe efficiency with which the purging process takes place.

In one embodiment, multiple ports are formed in the first furnacesurface and are disposed in a pattern extending across the first furnacesurface. Thus, the ports are disposed adjacent to the forming sheet in apattern that extends across the forming sheet from one side to anopposite side forming sheet. This configuration will cause a desiredeven distribution of the gases across the forming sheet. A plurality ofpatterns may be used. For example, one pattern may be a line of portsextending across the first furnace surface and the second pattern may beV-shaped with a point of the V disposed in the mid-region of the surfaceand two sides of the V extending across the surface.

In accordance with a more particular embodiment, the furnace may beconfigured to form a confining space around the carrier substrate andthe forming sheet, and the confining space may be open to the atmospherearound the furnace. In this configuration, gas may flow out of thefurnace, but the confining space will restrict the flow of gas out ofthe furnace so that the confining space is continuously filled with thedesired gas. Also, an entrance may be formed in the furnace, penetratingthe confining space of the furnace and dimensioned to receive thecarrier substrate and forming sheet. The entrance may allow gases toflow out of the furnace, but it will be part of the confining space andwill restrict the flow of gases out of the confining space such that adesired gas is maintained within the confining space. A transportmechanism is provided for moving the carrier substrate and the formingsheet into the entrance of the furnace and within the furnace along adirection of travel. An exit, similar to the entrance, is also formed inthe furnace penetrating the confining space so that the transportmechanism may move the carrier substrate and the forming sheet along thedirection of travel and out of the furnace through the exit.

A gas chamber may be formed around the confining space of the surfacefor capturing and containing the purge gases and the donor gases thatflow out of the furnace. Thus, a gas atmosphere is formed within the gaschamber around the furnace that is substantially free of undesirablegases, such as oxygen. Thus, the gas chamber will protect the furnacefrom infiltration of undesirable gases from outside the furnace. The gaschamber is preferably formed by a hood system that contains the entirefurnace, and gases within the hood system may be controlled by a varietyof mechanisms. For example, gases may be released from the hood systemat a controlled rate that is substantially equal to the rate at whichgases are introduced into the furnace. Thus, the hood system may remainslightly pressurized with respect to the outside atmosphere so thatgases flow out of the furnace into the gas chamber, and out of the gaschamber into the surrounding environment or atmosphere.

The furnace may also be provided with a plurality of carrier substratesand the forming sheet may be one or more forming sheets suitable forgrowing graphene with at least one forming sheet disposed on each of theplurality of carrier substrates. So, the number of forming sheets may beequal to the number of carrier substrates or may be greater than thenumber of carrier substrates. Multiple forming sheets may be carried oneach carrier substrate. Alternatively, a single forming sheet could becarried by multiple carrier substrates. In such case, at least oneforming sheet would still be disposed on each of the plurality ofcarrier substrates. The transport mechanism is configured to move theplurality of carrier substrates into the entrance of the furnace,through the furnace along a travel path and out the exit of the furnace,so that graphene is grown on each forming sheet as it is heated andpassed through the donor gases in the furnace.

The method of making graphene as described above may be described asintroducing a purge gas into a space within a furnace to purge the spaceof undesirable gases such as oxygen and introducing a donor gas into thespace. A forming sheet suitable for forming graphene is moved within thespace when the donor gases are within the space, and the forming sheetis heated within the space to a temperature sufficient to form 2Dmaterial. Thus, 2D material is formed on the moving forming sheet withinthe furnace.

In accordance with a more particular method of making 2D material,multiple carrier substrates are used and new carrier substrates arecontinuously moved into the furnace to form a train of carriersubstrates that moves into and through the furnace. At least one formingsheet is disposed on each carrier substrate and each forming sheet isheated as it moves through the furnace to a temperature sufficient toform 2D material on the forming sheet. After the forming sheet isheated, each forming sheet is exposed to a donor gas to form 2D materialon the forming sheet. Then, each carrier and forming sheet is moved outof the furnace through the exit.

In accordance with another aspect of the method, purge gases areintroduced into a confining space within the furnace and into a gaschamber surrounding the furnace. Thus, purge gases continuously flowinto and out of the confining space and the gas chamber until the gaschamber and space are substantially oxygen free. Then, donor gases areintroduced into the confining space and the donor gases flow out of thefurnace into the gas chamber. At least some of the purge gas and thedonor gas that escapes from the confining space within the furnace iscaptured and retained in the gas chamber to maintain an environment inthe gas chamber around the furnace that is substantially free ofundesirable gases such as oxygen.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may best be understood by considering non-limitingexamples described below when considered in conjunction with thedrawings in which:

FIG. 1 is a perspective view of a furnace having multiple modularsections for manufacturing 2D materials such as graphene;

FIG. 2 is a different perspective view of the furnace showing cartridgesbeing inserted into the entrance of the furnace;

FIG. 3 is a close-up perspective view of the entrance to the furnace;

FIG. 4 is a detailed perspective view of one section of the furnaceshowing the gas delivery system;

FIG. 5 is another detailed perspective view of one section of thefurnace showing a V-shaped gas injection manifold for delivering gas tothe furnace;

FIG. 6 is a detailed perspective view of a gas mixing system fordelivering gas to the furnace;

FIG. 7 is an illustration of the float table that functions as a supportfor the cartridges carrying the forming sheet;

FIG. 8 is a top perspective view of a cartridge;

FIG. 9 is a somewhat diagrammatic cut-away section view of gas isflowing within the furnace;

FIG. 10 is a somewhat diagrammatic cut-away section view of gas flowingwithin the furnace;

FIG. 11 is an illustration of flow within the furnace showing gasflowing out the entrance and the exit of the furnace;

FIG. 12 is an illustration of multiple patterns of gas ports integratedinto quartz plates with one of the patterns being V-shaped and theremainder being linear;

FIG. 13 is a perspective somewhat diagrammatic view of a furnace sectionshowing that the heaters are above the gas ports and that the gas boardsare above the reaction chamber;

FIG. 14 is a perspective illustration of two quartz plates in which gaspassageways and gas ports have been formed;

FIG. 15 is another illustration of a section of the furnace showing theintegrated gas passageways and ports formed in two quartz plates; and

FIG. 16 is and illustration of gas passageways and ports formed into apair of patterns formed by two quartz plates.

DETAILED DESCRIPTION

One embodiment of a 2D manufacturing machine 20 is shown in the FIGS. 1and 2 and this particular machine is well suited for manufacturinggraphene. In the discussion below, these embodiments will be discussedwith respect to graphene, but it will be understood that the machine andmethods may also be applied to the manufacture of other 2D materials.This particular embodiment has 11 separate sections 61 with each section61 receiving water through water pipes 28 for cooling the section. Thus,the sections 61 may be identified as the equipment attached to thegrouped water pipes 28. The 11 sections 61 form a reaction chamber 24 inwhich graphene is deposited on a copper forming sheet 23 which isstretched across the top of a cartridge 22. The cartridges 22 arepropelled on a cushion of gas through the reaction chamber 24 and asthey progress through the chamber, the copper forming sheets 23 areheated to a range of 900 to 1060 centigrade. In this embodiment, thetemperature is approximately 1030 degrees centigrade. The atmosphereabove the cartridges is first purged with an oxygen free gas tosubstantially eliminate the presence of oxygen within the reactionchamber 24. The purge gas is nitrogen. In alternate embodiments, thepurge gas may be other gases such as argon. Also, in alternateembodiments the machine 20 may be air cooled or not cooled at all.

Near the middle and end of the reaction chamber 24 reaction gases areintroduced to deposit graphene on the copper forming sheet 23. One ofthe reaction gases supplies carbon atoms to form graphene on the copperforming sheet 23, and it is referred to as the carbon supply gas. In oneembodiment, the carbon supply gas is natural gas (methane). In otherembodiments, the carbon supply gas could be Acetylene, Butane, Ethane orother carbon based gases. In addition, facilitating gases are introducedto help regulate and facilitate the reaction and in this embodiment, thefacilitating gases are Hydrogen, Nitrogen, Helium or Argon.

The cartridges 22 and the copper forming sheets 23 are introduced intothe front of the reaction chamber 24, which is the near end as shown inFIGS. 1 and 2 . The cartridges 22 move from the front end to the rearend of the reaction chamber 24, and as they enter the chamber 24 a purgegas is introduced through manifolds 26. Each of the sections 61 of thereaction chamber 24 are constructed from quartz. In alternateembodiments fused silica, fused quartz or ceramics may be used. Themanifolds 26 apply gases to the top of the reaction chamber 24 and holesare provided below the manifold so that gas escapes from the manifoldinto the chamber. The purge gases flow toward the front end of thereaction chamber 24. In this embodiment, the first and second sections61 of the reaction chamber 24 introduce purge gases through themanifolds 26 and the flow is toward the front of the reaction chamber24. Each of the sections 61 of the reaction chamber 24 is cooled by ajacket of water which is provided by water pipes 28. In the first twosections 61 of the chamber 24, the process of heating the copper formingsheet 23 is begun. Infrared heating tubes are provided inside thechamber 24 above the copper forming sheet 23 and induction heaters areprovided below the forming sheet 23 and below the cartridge 22. As thecartridges progress through the reaction chamber 24 the temperature ofthe copper forming sheet 23 is raised to approximately 1030 before thecartridge 22 reaches the third section. Purge gases are supplied to thethird section by the inputs 33 and the mixing manifold 35.

When the cartridges 22 reach the fourth section, the gas mix is changedto create a gas mixture that will deposit graphene on the copper formingsheets 23. Thus, mixing manifold 35 supplies a mixture of reaction gasesand facilitating gases to a V-shaped manifold best shown in FIG. 2 . Thedeposition of graphene on the copper forming sheets 23 begins at thepoint of the V-shaped manifold 39 and progresses outwardly in bothdirections as the cartridge moves through the reaction chamber 24. Thegraphene deposited at the point of the V-shaped manifold 39 starts thedeposition process and the crystals grow outwardly left and right fromthe starting point. Likewise, the crystals grow longitudinally along theaxis of the reaction chamber as the cartridges move toward the rear ofthe chamber 24. The V-shape is one example of a way to implement theinvention. In alternate embodiments, the manifold could be linear andinclined with respect to the motion of the copper, or linear andperpendicular to the direction of motion. It could also be stairstepped. The cartridges are also intended as a non-limiting example ofone embodiment. In alternate embodiments, the copper forming sheet maybe transported through the reaction chamber on a continuous copperforming sheet that comes off a roll at one end and is reeled onto a rollon the opposite end of the reaction chamber. Moving structure, such asfloating cartridges, rollers or moving belts may be used to support thecopper forming sheet as it moves through the reaction chamber in thisembodiment.

A more detailed view of the front end of the machine 20 is shown in FIG.3 . When the cartridges 22 are first loaded into the machine 20, theyare initially supported on rollers 38 and they are driven forward intothe reaction chamber 24 by belts 36 (or other drive mechanisms) whichengage the sides of the cartridges 22. As the cartridges 22 enter thereaction chamber 24 they are supported on a cushion of gas that issupplied by a gas table that extends for the length of the reactionchamber 24. The width of the reaction chamber is the horizontal internaldiameter of the furnace 42 in a direction perpendicular to the directionof travel of the sheets 23. The height of the reaction chamber is thevertical distance as shown in FIG. 3 from the sheet 23 to the interiortop of the furnace 42. The width is at least 3 times the height but thewidth is less than 1,000,000 times the height. Preferably, the width isless than 1000 times the height. The configuration of the volumecombined with the configuration of the ports and the flow rates of thegases is designed to produce a substantially nonturbulent, laminar flowof the donor gases across the forming sheet 23. The purge gases willalso have the nonturbulent laminar flow across the forming sheet whichwill increase the efficiency with which the purging process takes place.The gas table is best shown in FIG. 4 which shows the entrance of thereaction chamber 24 with the cartridges removed. The gas table 44includes a plurality of holes in the top of the table through which gasis forced. Since this gas is released into the reaction chamber, it is agas that is substantially oxygen free. Thus, the gas table 44 floats thecartridges 22 in a manner similar to an air hockey table.

The top of the reaction chamber 24 is formed by a water cooling jacket48 that is supplied with cooling water by a water input 43 whichsupplies water to the cooling jacket 48 through water pipes 28. Water isforced through the water cooling jacket 48, drained from the jacket,cooled and recirculated through the water cooling jacket 48 again.

Gas is supplied to the reaction chamber 24 by a gas mixing and controlsystem 32 and a gas mixing manifold 30. In this embodiment, fivedifferent gases may be introduced by the control system 32, and thegases are mixed within the manifold 30. A gas mixing monitor receivesthe mix gas from the manifold 30 and supplies it to the manifolds 50. Inthis embodiment, each section of the reaction chamber 24 includes threegas mixing manifolds 50 supplied by three different gas mixing monitors54. The gas mixing manifolds 50 extend through the water cooling jacket48 and holes 51 are provided in the bottom quartz plate of the watercooling jacket 48. The manifolds 50 isolate the gas from the water inthe water cooling jacket 48 and the gas is injected through the holes 51into the chamber 24. In this embodiment, the holes 51 have a diameter of½ inch or less, preferably in the range of 0.35 to 0.02 inches. In thisembodiment, we use holes that are 0.3 for the reaction gases and 0.1 forthe purge gases.

That portion of the reaction chamber 24 shown in FIG. 4 is a section ofthe reaction chamber 24. The overall chamber 24 is created by providing11 of these sections 61 connected together and sealed sufficiently thatthey will contain the purge gases and the reaction gases. Since thereaction chamber 24 is under positive pressure, it is not necessary thatthe chamber be totally gas tight. To the extent that leaks exist in thechamber 24, the leaking gases will be exhausted from the reactionchamber 24 and recovered by an exhaust hood (not shown) that encompassesthe entire reaction chamber and captures escaping gases and heat.

Referring to FIG. 5 , a unique reaction chamber section 61 is shown. Itincludes a V-shaped gas injection manifold that extends from a point inthe center of the reaction chamber 61 and extends rearwardly to the leftand right edges of the section 61. Reaction gases are first introducedinto the V-shaped gas injection manifold so that graphene productionwill begin in the center of a copper forming sheet 23. As the copperforming sheet 23 continues to move toward the rear of the reactionchamber 61, the graphene crystal may grow on a longitudinal lineparallel to the direction of travel. At the same time, the graphenecrystals may begin to grow outwardly laterally toward the left and rightlateral edges of the section 61. Thus, the graphene may grow in aV-shaped pattern that will maximize the crystalline size of thegraphene. The initial graphene created near the center of the V-shapedmanifold 60 will form a crystal structure that may be propagatedlongitudinally and laterally (left and right) as the copper formingsheet 23 continues to move through the section 61.

In the view of FIG. 5 , the gas table 44 and the holes 45 are shownimmediately below the water cooling jacket 48. As previously discussed,the cartridges 22 float on the top of the gas table 44, and the copperforming sheet 23 is disposed on the top of the cartridge 22. Thus, thedistance between the copper forming sheet 23 and the bottom of the waterjacket 48 is approximately 1 or 2 inches to allow enough room for heatlamps. The flows of gases have been acceptably uniform with the 1-inchspacing between the gas holes and the copper forming sheet 23, but asdiscussed below, a smaller distance, of approximately 0.3 inches,provides improved uniform non-turbulent flow. The separation distancebetween the copper forming sheet and the bottom of the water jacket 48is optimized to provide the best uniform gas flow, and providesufficient clearance to insure no accidental contact between the copperforming sheet 23 and the quartz bottom of the water jacket 48.

Referring to FIG. 6 , a detailed view of the gas input section 61 isshown. Five gas controllers 32 introduce gas into a mixer manifold 30which mixes the five gases before transmitting the gases further. Acutaway view of the mixer manifold 30 is shown in FIG. 6 revealing thatthe manifold 30 includes a plurality of baffles 31 that are designed tothoroughly mix the gases within the manifold. At the beginning of thereaction chamber 24, only inert gases are introduced into the reactionchamber 24. Thus, five inputs and a mixing manifold 30 are notnecessarily required at the front end of the chamber 24. However,including the five controllers 32 provides redundancy in case one ormore of the controllers fails and also provides flexibility in casedifferent types of inert gases are desired. Likewise, the fivecontrollers 32 provide flexibility and redundancy in the more rearwardsections 61 where inert gas, carbon supply gas and facilitating gas isintroduced. While five gases are used in this embodiment, otherembodiments may use more or fewer gases and other 2D materials may beproduced such as Boron Nitride.

Referring to FIG. 7 , a reaction chamber section 61 is shown in a cutaway view with the water jacket 48 removed. The section 61 as shown inFIG. 7 is completely constructed of quartz in this embodiment. Inalternate embodiments, it may be constructed of other materialsincluding ceramics. Although the various components of the section 61and the machine 20 are shown as single components, such as single quartzplates, those components may be constructed of multiple components, sucha multiple quartz plates, to better contain and control gas flow withinthe machine 20. The gas table 44 includes a plenum chamber 80 below thetop 81 of the table. The plenum chamber 80 is bounded on the left andright sides by table plate 78 and table plate 74. Chamber sidewalls 76and 72 form the left and right sides of the reaction chamber 24, andreturn passageways 70 and 68 are formed adjacent to the wall 76 and 72.When a cartridge 22 is placed on the tabletop 81, it wraps around theside table plates 74 and 78, and gas on which the cartridge 22 isfloating will escape from underneath the edge of the cartridge 22 alongthe lower side of the return passageways 68 and 70. This inert gas isexhausted from the reaction chamber 24 through the passageways 68 and 70and does not significantly escape upwardly towards the tabletop 81.Thus, the inert gases on which the cartridges 22 are floating are notallowed to interfere with the reaction occurring on the top of thecartridge 22.

FIG. 8 shows a detailed view of a cartridge 22 that is completelyconstructed of quartz in this embodiment. At the rear end of thecartridge 22 a groove 82 is formed for interlocking with anothercartridge 22. Likewise, on the forward end of the cartridge 22 aninterlocking rib 84 is formed. The front and rear of the cartridge 22are configured so that the rib 84 fits snugly within the groove 82 and asmooth continuous surface is formed a between the forward and of onecartridge 22 and the rearward end of another cartridge 22. Also, in thisview may be appreciated that the copper forming sheet is stretchedacross the cartridge and bends around the left and right corners of thecartridge. The ends of the copper forming sheet 23 are disposed inV-shaped grooves 86. Then, a locking mechanism is inserted into thegrooves 86 to lock the copper forming sheet 23 and place across thecartridge 22. In this embodiment, the copper forming sheet 23 might alsobe referred to as a copper foil. It has a thickness of approximately 5to 20 mils. Thinner copper foil is generally better, and in oneembodiment the foil is 3 mils in thickness. However, the copper formingsheet 23 may be thicker than 20 mils and may be characterized as aplate.

FIGS. 9 and 10 show cutaway views of the reaction chamber 24. As shownin these views, a plurality of infrared heating tubes 90 are mountedalong the top of the reaction chamber immediately below the coolingjacket 48. A plurality of induction heaters may be mounted in thechamber 24 within plenum chamber 80 formed by the cartridges 22. Theinduction heaters directly heat the copper forming sheet 23 withmagnetic fields that establish eddy currents in the copper formingsheet. Also, the connections between adjoining cartridges 22 is shownwith a rib 84 from one cartridge mating with a groove 82 from anothercartridge. In alternate embodiments, the induction heaters may beomitted.

Manifolds 50 introduce gas into the reaction chamber 24 with themanifold 50-1 schematically representing the middle or dividingmanifold. Gas flowing from manifold 50-1 flows both forwardly andrearwardly, whereas gas flowing from manifold 50-2 flows only in theforward direction and gas flowing from manifold 50-3 flows only in therearward direction. In this embodiment, reaction gases are introducedonly rearwardly from the manifold 50-1 and thus only inert gases flowout of the front of the reaction chamber 24. Referring to flow lines 88and 92, it will be appreciated that the gas pressure created bymanifolds 50 in the top of the reaction chamber 24 exceeds the gaspressure created by the gas table 44. Thus, the gases from the top ofthe reaction chamber 24 flow downwardly into the passages 68 and 70 aswell as rearwardly and forwardly through the reaction chamber 24.

FIG. 11 illustrates the entire length of the reaction chamber 24 andshows the flow gradient within the chamber 24. The light-colored flowlines 94 represent forward flow toward the front of the reaction chamber24 whereas the darker flowlines 96 represent a rearward flow toward therear of the reaction chamber 24. The gray or medium flowlines 98 in themiddle of the reaction chamber 24 represent slow flow rates. Thus, itmay be appreciated that the flow basically starts near the middle of thechamber 24 and flows forwardly and rearwardly from the middle.

To begin operation of the graphene manufacturing machine 20, blankcartridges 22 without the copper forming sheets 23 attached are loadedinto the machine 20 from one end to the other. The machine 20 is thenpreheated and sensors are disposed along the length of the machinemeasure the temperature of the gas within the reaction chamber and thetemperature of the top of the cartridges. For example, in the embodimentof FIGS. 12-15 , the sensors are mounted in the bottom of the gas feedquartz plates 120 and the sensors may monitor both gas temperature andthe surface temperature of the cartridges based on radiant heat from thecartridges. When the temperature of the top of each cartridge in thethird section from the front to the rear section of the machine havereached operating temperature, approximately 1030 degree centigrade, thegases are turned on. Alternatively, the purge gases may be turned onbefore the heating process has begun or during the heating process.Typically, the donor gases and the facilitating gases would be turned ononly after the operating temperature has been reached, but it would alsobe possible to begin introducing donor and facilitating gases evenbefore operating temperatures are reached. The purge gases that areexiting the front of the machine 20 are collected by a hood system andare tested to ensure that the purge gases are substantially oxygen free.The gases exiting the rear of the machine are likewise collected by aseparate hood system (or the same hood system) and are tested to ensurethat the gases have the proper mixture of inert gas, facilitating gasand carbon supply gas (donor gas).

Once it is determined that the gases are proper and that the operatingtemperatures have been achieved, the first cartridge 22 loaded with acopper forming sheet 23 is introduced into the front end of the reactionchamber 24. The belts 36 drive each cartridge into the reaction chamber24 and each cartridge 22 pushes the cartridge 22 in front of it. Thus,the belts 36 push the entire train of cartridges 22 through the machine20. The cartridges 22 are pushed through the machine 20 as quickly aspossible and the speed is determined in part by the length of themachine. A longer machine with more sections 61 is capable of operatingat a faster cartridge speed. In general, the speed at which thecartridges may travel through the machine is determined by the length ofthe machine that is depositing carbon onto the copper forming sheet 23.For example, if that length is 10 feet and it is desired to expose thecartridges to the carbon supply gas for 10 seconds, then the cartridgesmay travel at a maximum speed of 1 ft./s through the machine. If thatlength is 20 feet and again it is desired to expose the cartridge 22 tothe carbon supply gas for 10 seconds, then the cartridges may travel ata maximum speed of 2 ft./s through the machine.

When the cartridges 22 exit the rear end of the machine, they aretransported to a processing area and the copper forming sheet 23 isremoved from the cartridge 22 and another copper forming sheet 23 ismounted on the cartridge 22. Then, the cartridge with the new copperforming sheet 23 is returned to the front of the machine and is againcycled through the machine to create another copper forming sheet 23with graphene deposited thereon.

The graphene is removed from the copper forming sheet 23 by a methodthat is dependent upon the desired use and condition of the graphene. Tomaintain the maximum integrity of the graphene, the copper forming sheet23 may be removed by substantially completely dissolving the copperforming sheet 23 in a bath of nitric or sulfuric or sulfurous or similaracid. To begin that process, an adhesive polymer forming sheet is firstapplied to the graphene on the copper forming sheet 23. Then, the copperforming sheet 23 is dissolved in the acid and the polymer forming sheetis used to handle the graphene and maintain the integrity of thegraphene during further processing. For example, it will normally benecessary to remove the acid from the graphene by flooding the grapheneand the polymer forming sheet with water and an isotonic solution.

The graphene may also be removed by a peeling process whereby again apolymer forming sheet is adhesively secured to the graphene. Then, a jetof fluid is applied to the intersection of the graphene and the copperforming sheet 23 to gently release the graphene from the copper formingsheet 23. In one embodiment, the jet of fluid may be a copper acid thatpartially dissolves the copper immediately adjacent to the graphene andcauses the graphene to be released from the partially dissolved copper.In this embodiment, an array of microjets and microfluidic pumps may beused to simultaneously begin the release of the graphene along theentire line or array. For example, the array of microjets may extendacross the width of the copper forming sheet 23 so that the graphene ispeeled as a single film from the copper forming sheet 23. Again, thepolymer forming sheet provides a substrate for the graphene to protectthe graphene and allow it to be handled more easily.

In this particular embodiment, each cartridge has a longitudinal lengththat is smaller than its width. The longitudinal length is parallel tothe direction of movement through the machine, and the width isperpendicular to the direction of movement. Preferably, the cartridge 22has a length of approximately 2 feet and a width of approximately 4feet. Thus, the copper forming sheet 23 applied to the cartridge 22 willalso have a length of approximately 2 feet and a width of approximately4′10″. The additional 10 inches is desirable to allow the copper formingsheet 23 to wrap around the cartridge 22 and fit into the clampinggroove 87 on the underside of the cartridge 22. Thus, in this embodimenteach cartridge 22 may produce a graphene forming sheet having maximumdimensions of approximately 2′×4′. However, depending upon the processfor removing the graphene from the copper forming sheet 23, it may bedesirable to remove sections 61 of the graphene from the copper formingsheet 23, and it may be desirable to cut the copper 23 forming sheetinto sections 61 before removing the graphene.

Referring now to FIG. 12 a large-scale graphene machine 100 is shownconstituting another embodiment. A hood system 101 is schematicallyrepresented, and it collects and retains gas that escapes the machine100 to provide a desired atmosphere or environment around the machine100. The machine 100 is similar to the machine described above exceptthat it distributes gas to the reaction chamber through integrated gascircuits 104 and 106. The integrated gas circuits are etched into asubstrate such as quartz and the etched gas circuits are covered with athin plate which may also be quartz. Laser etching may be used to etchthe gas circuits 104 and 106 into the substrate. The materials of theintegrated gas circuits 104 and 106 are selected to be transparent ornearly transparent to infrared heat. More specifically, the material ischosen to be as transparent as possible to near infrared heat having awavelength of between 0.6 μm and 2 μm. Quartz is an ideal material forthe substrate because it is practically transparent to near infraredheat.

Two different types of integrated gas circuits may be used. The gascircuit 104 is a linear circuit meaning that it discharges gas throughholes that are positioned in a line. Preferably, the line isperpendicular to the travel direction of the cartridge 102. The gascircuit 106 is a V-shaped circuit meaning that the discharge holes arepositioned in a V and distribute the gas onto the cartridge 102 withinthe reaction chamber in a V-shape which is similar to the V-shape of theV-shaped manifold 60 described above.

The cartridge 102 is similar to or identical to the cartridges describedabove. In this particular embodiment it is preferred to use a cartridgehaving the dimensions of 2′×2′, but smaller or larger cartridges couldbe used. As shown in FIG. 12 , the reaction chamber 24 is immediatelybelow the integrated gas circuits 104 and 106. Thus, the gas is releasedfrom the gas circuits 104 and 106 at a distance that is very near thetop surface of the cartridge 102. For example, the distance between thebottom of the holes releasing the gas in the top surface of cartridge102 may be about ¼ inch, and a spacing of ⅛ inch is desirable if thetolerances of the machine components will allow such spacing. Oneadvantage of releasing the gas in close proximity to the top surface ofthe cartridge 102 is the creation of a very smooth laminar flow of gasin both the forward and reverse directions. In addition, the machine 100does not include heaters in the reaction chamber 24. The heaters aredisposed above the integrated gas circuits 104 and 106, and arepreferably near infrared heat sources. Thus, the heat is transmitteddirectly through the integrated circuits 104 and 106 onto the cartridges102 and no heaters are disposed in the reaction chamber 24. If desired,induction heaters may also be used in the manner described with respectto the prior embodiments, but the near infrared heaters alone aresufficient for most applications.

A configuration of heaters is shown in FIG. 13 in which a heater box 110is mounted directly above a gas circuit 106. In this view, the top ofthe heater box 110 is shown to be semitransparent so that a plurality ofnear infrared heater lamps 112 may be seen within the heater box 110.The top is usually opaque to visible light. The lamps 112 are paralleltubes extending across the width of the gas circuit 106 in a directionperpendicular to the movement of cartridges 102 through the machine. Inthis configuration, the lamps 112 transmit a uniform heat patternthrough the integrated gas circuit 106 and onto the cartridge 102. Thecartridge is pushed through the reaction chamber 24 on a float table 118in a manner similar to that described with respect to previousembodiments. In this embodiment, ledges 114 and 116 are providedimmediately below the outer edges of the cartridge 102 and arepositioned so that there is a very small space between the ledges 114and 116 and the cartridge 102. The purpose of the ledges is not tosupport the cartridge and thus it is preferable that the ledges 114 and116 do not touch the cartridge 102. The purpose of the ledges is toprevent flow of gas in an upward direction from beneath the cartridge102 upwardly into the reaction chamber 24. The small spacing between theledges 114 and 116 and the cartridge 102 will prevent any significantflow of gas upwardly or downwardly around the edges of the cartridge102. However, in alternate embodiments, the cartridges may rest on theledges 114 and 116 and the cartridges may slide on the ledges on aquartz-to-quartz interface. In such embodiment, the float tables 118 maybe eliminated if desired.

In the view of FIG. 13 it may be appreciated that the spacing betweenthe gas circuit 106 and the cartridge 102 in the reaction chamber 24 isvery small, on the order of ¼ inch, and ⅛ inch is desirable. The quartzplates 120 that form the gas circuit 106 extend outwardly from the rightside of the reaction chamber 24 in the right side of the heat box 110for a distance of about 3 inches. One purpose of this extension is toprovide access to the gas circuit 106. A supply line 124 is formed inthe plates 120 and extends outwardly along the extension to a connector126 formed in the bottom of the plates 120. A gas supply may beconnected to the connector 126 and gas may be introduced through thesupply line 124 to the gas circuit 106.

A detailed view of the two quartz plates 120 is shown in FIG. 14 . Abase plate 132 has a thickness of about 0.25 inches and an upper plate134 is positioned over the base plate. The gas circuit 106 is etchedinto the base plate 132 and in this particular gas circuit, the channelsforming the gas circuit 106 are approximately 0.3 inches wide andapproximately 0.15 inches deep. Gas is supplied through a connector 136into a supply line 138. The supply line connects through a plurality ofbranch lines and 140, 142, 144, 146 and 147 to a plurality ofdistribution lines 148. A plurality of holes 150 are formed in the baseplate 132 extending from the ends of the distribution lines 148 to thebottom of the base plate 132. The holes 150 constitute nozzles having adiameter of approximately 0.30 inches that feed gas into the reactionchamber below the plate 132. The holes 150 are disposed in a V-shapethat points into or against the direction of travel of the cartridges asthey move through the machine. In this particular embodiment, theV-shaped of the holes 150 terminates at a double point formed by twoholes 152 that are aligned with each other along a line perpendicular tothe direction of travel of the cartridges. In this particularembodiment, the two holes 152 constitute the point of the V-shape. Asdiscussed above with regard to the V-shaped manifold, the purpose of theV-shaped is to promote the formation of a single large crystal beginningat the point of the V-shaped and growing as the cartridge moves furtheralong its path beneath the integrated gas circuit 106.

The linear integrated gas circuit 104 is illustrated in FIG. 15 . Again,the gas circuit 104 is formed by a baseplate 132 and the top plate 134.Preferably the gas circuit 104 is etched into the base plate in the topplate is sealed on top of the baseplate 132 to seal the top portion ofthe gas circuit 104. The linear gas circuit 104 includes a supply line160 that feeds branch lines 162, 164, 166, 168 and 170. A plurality ofdistribution lines 171 are connected between the branch lines 170 and aplurality of nozzles 172 that are formed through the baseplate 132. Thenozzles 172 are preferably simple holes that extend through thebaseplate to admit gas into the reaction chamber 24. The nozzles 172 arepreferably smaller than the nozzles used in the V-shaped gas circuit106. Thus, the nozzles 172 preferably have a diameter of approximately0.1 inches. The channels forming the branch lines and distribution lineshave a width of approximately 0.1 inches and in depth of approximately0.15 inches. The dimensions of the branch lines, distribution lines andnozzles (holes) are chosen to be sufficiently small to ensure uniformlaminar flow through the gas circuit to ensure uniform injection of gasinto the reaction chamber. The linear gas circuit 104 is constructedsuch that the overall length or distance from each nozzle 172 to thesupply line 160 is the same. Thus, the pressure drop from the supplyline 160 to each nozzle 172 should be the same.

In this view, the float table 174 is shown below the plates 132 and 134,but the cartridge has been removed. In this section the ledges 114 and116 are provided in the same position and for the same purpose aspreviously described. The flow tables emit an inert gas through theholes 176 to float the cartridges as they pass through the machine andthe ledges 114 and 116 substantially eliminate any gas flow into or outof the reaction chamber around the edges of the cartridge.

The two hole patterns described above are examples and other types ofpatterns for the gas a meeting nozzles may be used. In addition, othertypes and shapes of gas circuits may be used. For example, the V-shapedgas circuit may be formed by two linear gas circuits each of whichstarts in the center of the substrate (quartz plate) and extendsrearwardly at an angle of +45° and −45° with respect to the direction ofmovement of the cartridge beneath the integrated gas circuit. Likewise,a single linear gas circuit may start at one edge of the substrate andextend to the opposite edge of the substrate and extend rearwardly at anangle of approximately 45° with respect to the direction of the movementof the cartridge. The purpose of the V-shaped and the inclined shape isto start the formation of graphene crystals at a substantially singleposition so that the crystal structure can grow from a single positionand thereby produce larger crystals.

In this particular embodiment of FIGS. 12-15 the flow of gases isparticularly easy to control and is uniform, smooth and laminar. Tobegin the flow of gases within the machine, inert gases may be usedthroughout the entire machine. The inert gases will purge the machineand will establish desired flow patterns. Once these flow patterns havebeen established they will continue unchanged absent disturbances. Thus,the flow patterns may be established with inert gases and then thereaction gases may be introduced at a later time after the flow patternhas been established.

The cartridges used in all embodiments may be constructed in differentmanners depending on the type of production desired. For example, if amachine is to be used only with near infrared heat lamps, the copperfilms as described in the first embodiment above provide a suitablereceptor for the graphene. However, if it is desired to use inductionheaters, the cartridge 102 may be constructed with a tungsten layerbeneath the copper. Tungsten and copper repel each other chemically andresist bonding one to the other. Thus, tungsten is a desirable materialfor use as the first layer on the top of the cartridge 102. Even at hightemperatures the copper film will not bond or adhere to the tungstenlayer. Also, the tungsten layer is electrically highly resistive and isa good material for use in inductive heating. Because of its highresistance it is unlikely to develop eddy currents and hotspots and itrapidly transmits heat to the adjacent copper. Thus, the tungsten willaid in the uniform heating of the copper.

To minimize heat requirements, the tungsten and copper layers on thecartridge 102 may be made as thin as possible. For example, it may bedesirable to sputter, metalize or otherwise apply a thin layer oftungsten onto the cartridge 102 and then heat the cartridge and tungstento anneal the tungsten and create a smooth surface for supporting thecopper layer. The copper layer may be a self-supporting film that isphysically applied to the tungsten layer, or the copper layer may beapplied to the tungsten layer by metallizing techniques such assputtering, vacuum metallizing, thermal spraying, cold spraying or othermetallizing techniques. After the graphene layer has been deposited onthe copper layer, the process may be repeated. That is, the cartridgemay be reused and copper or another suitable material may be applied ontop of the graphene layer. Then, the cartridges reintroduced into thereaction chamber and the process is repeated to apply another layer ofgraphene on top of the new layer of copper or other suitable material.This process may be repeated a number of times as desired to produce amultilayered structure of graphene layers and metallic layers.Alternatively, the graphene layers in the metallic layers may beseparated in the graphene recovered for applications requiring onlygraphene.

Referring to FIG. 16 , the quartz plates 134 and 132 may also be used toincorporate a groove in which to mount sensors for monitoring thetemperature of the copper in the combustion chamber below the quartzplate 132. A wide variety of sensors may be mounted in the groove 180that is preferably etched into the quartz plate 132, but it may also bemachined or otherwise formed. A preferred sensor would be a radiant heatsensor that is focused downwardly looking through the bottom of thequartz plate 132 and measures the temperature of the copper formingsheet on which the graphene or other product will be formed. The sensorsare useful for starting the manufacturing process and for detectingfaults or errors in the manufacturing process but are not absolutelynecessary for the manufacturing itself.

What is claimed is:
 1. A method of making 2D material comprising:providing a reaction chamber including: a gas confining space extendingthrough the reaction chamber from a chamber entrance to a chamber exit,the chamber entrance and chamber exit being open to a surroundingatmosphere, a support extending through the gas confining space of thereaction chamber from the chamber entrance to the chamber exit, and aplurality of carriers positioned on the support, each of the pluralityof carriers including a forming layer suitable for producing 2D materialdisposed on a surface of the carrier, introducing one or more purgegases into the gas confining space to purge the gas confining space ofoxygen and to establish a laminar flow of gases throughout the gasconfining space, the laminar flow of gases consisting of a first forwardflow path from a middle portion of the gas confining space through thechamber entrance and a second rearward flow path from the middle portionof the gas confining space through the chamber exit; introducing a donorgas into the laminar flow of gases after the laminar flow of gases hasbeen established; moving the plurality of carriers along the supportthrough the gas confining space from the chamber entrance and throughthe chamber exit while the chamber entrance and chamber exit are open toa surrounding atmosphere and the donor gas is being introduced into thegas confining space; maintaining a positive pressure relative to thesurrounding atmosphere throughout the gas confining space during themoving step; and heating the forming layers to a temperature sufficientto produce 2D material as the plurality of carriers are moved throughthe gas confining space.
 2. The method of claim 1 wherein the step ofintroducing the donor gas includes supplying the donor gas into the gasconfining space at a flow rate that produces a non-turbulent, laminarflow of donor gas across the forming layer during production of 2Dmaterial on the forming layer.
 3. The method of claim 1 wherein the stepof introducing the donor gas includes continuously introducing at leastthe donor gas into the gas confining space of the reaction chamber afterpurging the gas confining space of the reaction chamber and the step ofmoving the plurality of carriers includes continuously moving newcarrier substrates with at least one forming layer on each carriersubstrate through the reaction chamber to form a stream of carriersubstrates that moves into and through the gas confining space of thereaction chamber.
 4. The method of claim 1 wherein the step ofintroducing purge gas into the gas confining space includes flowing thepurge gas out of the gas confining space through at least the chamberentrance.
 5. The method of claim 1 further comprising continuouslyintroducing at least one of the purge gas, the donor gas, and acombination thereof into the gas confining space for maintaining thepositive pressure.
 6. The method of claim 5 further comprisingcontinuously flowing at least a portion of the continuously introducedgases in a first direction for maintaining the first forward flow paththrough the chamber entrance and continuously flowing at least a portionof the continuously introduced gases in a second direction formaintaining the second rearward flow path through the chamber exit. 7.The method of claim 1 further comprising positioning each of theplurality of carriers on the support to form a train of carriers, andwherein the moving step further includes driving the train of carriersthrough the gas confining space such that each carrier pushes anothercarrier in front of the carrier.
 8. The method of claim 7 furthercomprising providing a drive mechanism disposed at least partiallyoutside the gas confining space driving the train of carriers throughthe gas confining space along the support.
 9. A method of forming 2Dmaterial comprising: providing a reaction chamber including a gasconfining space extending through the reaction chamber from a chamberentrance to a chamber exit, a support extending through the gasconfining space, and a plurality of carriers positioned on the supportfor supporting a forming layer suitable for forming 2D material, thechamber entrance and the chamber exit being open to the atmospherearound the reaction chamber; heating the gas confining space;introducing one or more purge gases into the gas confining space topurge the gas confining space of oxygen and to establish a laminar flowof gases throughout the gas confining space, the laminar flow of gasesconsisting of a first forward flow path from a middle portion of the gasconfining space through the chamber entrance and a second rearward flowpath from the middle portion of the gas confining space through thechamber exit; introducing a donor gas into the laminar flow of gasesafter the laminar flow of gases has been established; positioning theforming layer on the plurality of carriers; moving the plurality ofcarriers along the support through the gas confining space from thechamber entrance and through the chamber exit to react with the donorgas to form 2D material while the gas confining space is open to theatmosphere; and maintaining a positive pressure relative to thesurrounding atmosphere throughout the gas confining space during themoving step.
 10. The method of claim 9 wherein the forming layerincludes a plurality of forming layers each carried by one of theplurality of carriers.
 11. The method of claim 9 wherein the forminglayer includes a single forming layer carried by two or more of theplurality of carriers.
 12. The method of claim 8 wherein the moving stepfurther includes driving the plurality of carriers along the support viaone or more drive surfaces disposed at least partially outside the gasconfining space.
 13. The method of claim 12 wherein the plurality ofcarriers are supported by a plurality of rollers as they are drivenalong the support.
 14. The method of claim 9 wherein the moving stepfurther includes propelling the plurality of carriers on a cushion ofgas through the gas confining space.
 15. The method of claim 9 whereinthe forming layer is a continuous sheet secured at a first end by afirst roller adjacent the chamber entrance and secured at a second endto a second roller adjacent the chamber exit, the moving step furtherincludes transporting the continuous sheet through the gas confiningspace by rolling the continuous sheet off the first roller onto thesecond roller while the forming sheet is supported by the plurality ofcarriers.
 16. The method of claim 9 wherein the heating step includesheating the gas confining space to a temperature of at least 900 C. 17.The method of claim 9 wherein the 2D material is graphene.
 18. Themethod of claim 9 wherein the reaction chamber is formed of one or morematerials selected from the group consisting of quartz, fused silica,fused quartz, and ceramics.
 19. The method of claim 1 wherein the stepof introducing the donor gas into the laminar flow of gases includesintroducing the donor gas into only the second rearward flow path. 20.The method of claim 9 wherein the step of introducing the donor gas intothe laminar flow of gases includes introducing the donor gas into onlythe second rearward flow path.